The primary objective of the proposed research is to participate in prospective, randomized controlled clinical trials of the NSABP to assess the value of various therapeutic regimens when employed in the adjuvant setting. The current protocols are concerned with both Stage I and II breast cancer patients; in both stages, estrogen receptor values are utilized in regimen determination. We will also participate in the testing of new therapies for such patients. An additional objective will be to participate in the collection of pertinent data from these trials to assist in the evaluation of present and new therapies. We will then disseminate the results of such clinical trials to the physicians in our institution and our community so that they better understand the need and justification for such studies and can then improve the care of their patients with breast cancer.